Devon Erickson, one of the two teenagers to be arrested for the May 2019 shooting at STEM School Highlands Ranch, pleaded not guilty on Thursday.

The Denver Channel reports that Erickson is charged with 44 felonies stemming from the murder of student Kendrick Castillo and the wounding of eight others.

Erickson’s attorneys may introduce subsequent evidence regarding the defendant’s mental condition. He will undergo an evaluation at the jail or a mental health facility.

Erickson was 18 at the time of the shooting and the other suspect, Alec McKinney, was 16. Last month, a Douglas County judge decided that McKinney would face trial as an adult.

At the time, 18th Judicial District Attorney George Brauchler said that “On behalf of the many, many victims and our community, I am satisfied and pleased that the court agreed that this mass shooting case should be resolved in adult court.”

As a result of the murder, Douglas County commissioners appropriated approximately $10 million to physical safety improvements and deployment of technology for county schools. Another $3 million went toward the hiring of school resource officers. Youth mental health funding amounted to $331,000.